Electromagnet



June 10, 1930.

E. PETZING ELEGTROMAGNET Filed Nov. 14, 1927 2 Sheets-Sheet 1 VE E June 10, 1930. w, PETZlNG 1,763,007

ELECTROMAGNET Filed Nov. 14, 1927 2 Sheets-Sheet 2 Patented June 10, 1930 PATENT OFFICE ERWIN WALTER PETZING, OF CHICAGO, ILLINOIS ELECTROMAGNET Application filed November 14, 1927. Serial No. 232,973.

This invention relates to improvements in electromagnets, and more particularly to a solenoid or electroniagnet utilizing a plurality of coils, a unitary core for the same, and a unitary plunger responsive to the energization of the aforesaid coils.

It has been found highly desirable to provide a device of the class described herein which under continuous operation will have a negligible temperature rise, does not chatter and is practically noiseless in operation, and which is automatic in its action.

In the past, devices of this type have proven objectionable in various ways. A common objection to these former known devices is that when under continuous operation there will be a material temperature rise which, in certain instances, may prove dangerous. Moreover, these devices in many cases were not sufliciently positive in their action, nor were they as compact in form as may be desired.

The present invention is designed to overcome the above noted defects and objections in the provision of an electromagnet which when under continuous use has an action akin to a transformer under no load, whereby the rise in temperature will be no ligible.

The invention also seeks to provi e a device of the class described herein embodying twin solenoids and a unitary core therefor which is adapted to automatically shift from starting coils to operating coils.

A further object of this invention is to provide a device of the class described which is quick and positive in its action and practically noiseless when operating.

A still further object of the present invention is to provide novel and compact means associated with the armature of the device to automatically cause the starting coils to be cut out of circuit and the operating coils cut in.

\Vhile some of the more salient features and characteristics of a device embodying this invention have been above pointed out, others will become apparent from the following disclosures.

The invention includes these and other features of construction and combinations of parts hereinafter described and shown in a preferred form in the drawings, as more particularly indicated by the claims.

In the drawings:

Figure 1 is a View in elevation showing a device embodying features of the present invention operatively connected for actu ating a valve or the like.

Figure 2 is a view in elevation of the device with the front portion of the cover removed.

Figure 3 is a central vertical sectional view, with parts in elevation, taken sub stantially along line III-III of Figure 2.

Figure 4 is a sectional view taken substantially along line IV-IV of Figure 2.

Figure 5 is a horizontal sectional view take; substantially along line V-V of Fig ure Figure 6 is a Vertical sectional View, with parts in elevation, taken substantially along shown, by bolts 3. Normally within the I Mounted to the upper portion of the frame is a unitary laminated core 10 having integral legs 11 and 12, respectively, thereon. The legs 11 and 12 are each provided with a coil or winding 13 and 14, respectively,

which are connected in series, as indicated Ii to extend therethrough.

at 15, and serve to complete a pair of solonoids on the unitary core.

Free to move in a reciprocatory manner within the channels formed between frame members 5 is a laminated plunger or armature 16 which is responsive to the energization of the coils 13 and 14. Secured to the bot-tom ot the plunger 16 is an insulated plate 17, the ends of which extend beyond the ends of the plunger to effectively guide the same within the frame. The plunger and plate 17 are apertured adjacent their central portion. as at 18, to permit a rod 19 The rod 19 is threaded at one end to engage within a re ciprocatory shaft 20 guided between the coils 13 and 14. The shaft 20 is provided with a flange 21 adjacent its lower end and the rod 19 is provided with a similar flange 22 adjacent its lower end, which serve to firmly clamp the armature when the rod 19 is tightened within the shaft 20. Ordinary insulating washers 23 are provided bet-ween the flanges and the armature. Preferably integral with the rod 19 and the flange 22 is a second reciprocatory shaft 24 which extends through the base plate 4 and the bottom of the casing 2, and to which may be connected any device to be actuated by the movement of the armature, or as is shown in Figure 1 the shaft 24 may be connected to actuate a valve 25.

Secured to the lugs 8 and 9 is a pair 01 vertically disposed insulated posts 26 and 27. respectively. one on each side of the armature 16. The post 26 is provided on one side thereof with a continuous contact plate 28 having a terminal 29 thereon, and on the other side with a second contact plate 30 which is split or divided as at 31, each half of which is provided with a terminal 32 and 33, respectively. The other insulated post- 27 is similarly provided with a continuous plate 34 with a terminal 35 thereon. and on the other side with a split plate 36 having terminals 37 and 38 on the parts thereof. It is L0 be noted that the plates 30 and 36 are separated adjacent their lower portions for a purpose that will later appear. Secured to the insulated plate 17 at each side of the armature 16 is a spring contact 39 and 40, respect vely. The contact 39 is provided with inwardly turned ends 41 and 42 adapted to slidably engage the plates 23 and 30, respectively; and the contact 40 provided with inwardly turned ends 43 and 44 adapted to slidably engage the plates 34 and 36, respectively.

As shown more clearly in Figure 8, the coils 13 and 14 are provided with permanent taps 45 and 46, respectively, at any desired point but preferably nearer one end than the other. The tap 45 on the coil 13 is connected through a conductor 47 to the terminal 33 on the lower portion of the split plate 30. The tap 46 is connected in a similar manner through a conductor 48 to the terminal 38 on the lower portion of the split plate 36. As hereinbefore stated the coils are connected at one end in series as indi cated at 15 in Figure 2. The other ends of the coils 13 and 14 are connected through conductors 49 and 50, res 'iectively, to the terminals 32 and 37, respectively, on the upper portions of the split plates 30 and 36, respectively. The terminals 29 and 35 on the continuous plates 28 and 34. respectively, are connected through leads or conductors 51 and 52, respectively, to the binding posts 53 and 54 projecting through the bottom 2 of the casing 1, which binding posts in turn are each connected to one of the line.

From the foregoing description of the connections it will be apparent that when the coils 13 and 14 are energized, the plunger 16 will start upwardly to eventually abut the projecting ends of the legs 11 and 12, the spring contacts 39 and 40 secured to the insulatii'ig plate attached to the plunger, will slide along the contact plates on the sides of the insulated posts 26 and 27. Each spring contact will complete the circuit from the plate on one side of the corresponding post to the contact plate on the other side of the post. It will be apparent, therc fore, by reference to Figure 8, that when the plunger starts to move, the spring contacts will establish a connection between the lower portion of each split plate and its corresponding plate. At this moment the current will travel from the line through conductor 51 to the continuous plate 28 on the post 26 through the spring contact 39 to the lower portion of the plate 30, through the conductor 47 to the permanent tap 45, and thence through only a small portion of the coil 13, through the connection 15 into a small portion of the coil 14; the current then leaves the coil 14 through the tap 46, conductor 48, into the lower portion of the split plate 36, through the spring contact 40, to the continuous plate 34 and then e back to the other side of the line through conductor After the armature has moved relatively short distance, the contacts 39 and 40 will engage with the upper portions of the split plates 30 and 36, respectively, and thereby cut in the entire coils 13 and 14. The current, in this case, will pass in the previously described manner from the line, through the contact into the upper portion of the split plate 30, then through lead 49 and the entire coil 13, into the coil 14. After passing through the entire coil 14 the current will leave through the conductor 50 into the upper portion of the split plate 36, into the contact 40, and back to the line as previously described. From these connections it is apparent that only a small portion of the coils 13 and 14,

or, in other words, a few turns of the same, are utilized, whereby a larger current is obtained to give the adequate flux density for setting the plunger in motion. Since the device of the present instance is connected across the line at all times, and the plunger during normal operation will be up or in abutment with the legs 11 and 12 of the core, very little current will be necessary to maintain the plunger in this position. Therefore, after the plunger has moved a relatively short distance, the entire coils 13 and 14 are cut in, thereby reducing the current to an operating minimum.

If any defect occurs in the line, or for some reason it is desired to discontinue operation, the line will be broken, the coils deenergized, and the plunger will drop to its original position, due to the action of gravity thereon. To hasten the dropping of the plunger when the circuit is broken or, in other words, to establish quick action in the device, a condenser 55 is connected directly across the line.

To eliminate objectionable noises, chattering, etc., the armature is provided with a pair of shading coils 56 and 57, which are disposed directly underneath the pole ends or the projecting ends of the legs 11 and 12. In this instance, the shading coils are not of an actual coil type but are small conductive cylinders preferably copper imbedded in the plunger 16. The present invention is highly desirable for use of single phase currents and since in single phase magnets the pull varies from zero to maximum and back twice during each cycle, the shading coils will split the phase so that flux is always present in the air gap and the pull is never zero, whereby the noise chiefly due to vibration is eliminated. When the present device is under operation there will be a very faint hum and otherwise no noise whatsoever.

It is to be especially noted in the operation of the present invention, that when the plunger is up in abutment with the ends of the legs 11 and 12, a substantially continuous core is provided with the winding on each leg thereof. The action of the device then will be in effect that of a transformer with no load on the secondary, and the temperature will rise only to a negligible amount. In fact, most of the rise in temperature for the present device, will be due to the induced current in the shading coil. Obviously, with such a limitation of a rise in temperature, the present device will be highly desirable for use in many and varied places with no damage resulting from overheating.

In the operation in connection with a valve as shown in Figure 1, when the device is operated in the previously described manner and the plunger rises, it will open the valve. The valve will be held open until a break in the circuit occurs when it will be closed by the fall of the plunger. It is to be distinctly understood, however, that the present invention is by no means limited to the action of a valve but may be used to actuate any desirable or suitable mechanism, and, of course, it is within the contemplation of this invention to actuate a rotary mechanism through means of a toggle connection to the shaft 24.

From the foregoing it is apparent that I have provided a novel and improved electromagnet, which is extremely compact in form, which automatically shifts from starting coils to operating coils, and which is so designed as to have an extremely small temperature rise during operation. Moreover, as constructed the present invention is extremely efiicient and accurate in its operation, very durable, and may be economically manufactured and operated.

I am-aware that many changes may be made and numerous details of construction may be varied through a wide range without departing from the principles of this invention, and I, therefore, do not purpose limiting the patent granted hereon otherwise than necessitated by the prior art.

I claim:

1. A, device of the class described suitable for both direct and alternating currents including a core, a pair of legs integral therewith, a coil on each of said legs, a plunger for abutting the ends of said legs when said coils are energized, and means operable by said plunger to connect a small portion of each coil in a circuit until said plunger is in motion, and then to connect all of said coils in circuit to hold said plunger in abut ment with the ends of said legs.

2. In a device of the class described, a core including a plurality of legs, a coil on each of said legs, a plunger responsive to the energization of said coils, contact plates adjacent said plunger, and means carried by said plunger and slidable on said plates to make and break circuits through said coils.

3. In a device of the class described, a core, coils thereon, an armature, split contact plates adjacent said armature and individual to each coil, one end of a coil being connected to one portion of a split plate, said coil being connected at a predetermined point to the other portion of said plate, the other ends of said coils beingconnected in series, and. means associated with said armature to slidingly engage said split plates to firstly connect one portion of each of said coils in circuit and lastly the whole of said coils.

4. In a device of the class described, means for producing a magnetic field, an armature responsive to the energization of said field, contact plates adjacent said armature, an insulated member carried by said armature, and resilient contacts on said member adapted to slidingly engage said plates to make and break circuits to vary the strength of said magnetic field.

In a device of the character described, a laminated core having a plurality of integral legs, a coil on each of said legs, a laminated movable member responsive to the energization of said coils, and means actuated by said movable member for connecting varying portions of said coils in the circuit which energizes the same.

(3. In a device of the character described a core having a plurality of integral legs, a coil on each of said legs, said coils being connected in series, movable means for abutting the ends of said legs in response to the energization of said coils, and means actuated by said movable means for successively causing the energization of varying portions of said coils.

7. In combination, conductive means for carrying an electric current, and means for varying the character of said current in eluding means movable in response to the energization of a portion of said conductive means, spaced sectioned members in proximity to said movable means, and means operated by said movable means for successively connecting portions of said sectioned members for causing said current to flow through various portions of said conductive means.

8. In combination, means for establishing a magnetic field when at least a portion of said means are included in an electric circuit, movable means responsive to said magnetic field, spaced sectioned members each having sections connected to various portions of said first mentioned means, and means carried by said movable means for successively connecting corresponding portions of said members to vary the strength of said field by including portions of said first mentioned means in said circuit.

9. A device of the character described designed for continuous as Well as intermittent use, said device including a laminated core having a plurality of integral legs, a coil on each of said legs, said coils being connected in series, a laminated movable member responsive to the energization of said coils to abutthe ends of said legs intimately to term substantially an integral core with said windings being on opposite legs thereof so that while said coils are energized said device has an internal effect the same as a transformer under no load.

In testimony whereof I have hereunto subscribed my name at Chicago, Cook County, Illinois.

ERVIN VALTER PETZING. 

